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RedHat 9 (Linux i386) - man page for mount (redhat section 8)

MOUNT(8)			    Linux Programmer's Manual				 MOUNT(8)

       mount - mount a file system

       mount [-lhV]

       mount -a [-fFnrsvw] [-t vfstype] [-O optlist]
       mount [-fnrsvw] [-o options [,...]] device | dir
       mount [-fnrsvw] [-t vfstype] [-o options] device dir

       All  files  accessible  in a Unix system are arranged in one big tree, the file hierarchy,
       rooted at /.  These files can be spread out over several devices. The mount command serves
       to  attach  the	file  system  found  on some device to the big file tree. Conversely, the
       umount(8) command will detach it again.

       The standard form of the mount command, is
	      mount -t type device dir
       This tells the kernel to attach the file system found on device (which is of type type) at
       the directory dir.  The previous contents (if any) and owner and mode of dir become invis-
       ible, and as long as this file system remains mounted, the pathname dir refers to the root
       of the file system on device.

       Three forms of invocation do not actually mount anything:
	      mount -h
       prints a help message;
	      mount -V
       prints a version string; and just
	      mount [-l] [-t type]
       lists  all  mounted  file  systems (of type type).  The option -l adds the (ext2, ext3 and
       XFS) labels in this listing.  See below.

       Since Linux 2.4.0 it is possible to remount part of the file hierarchy somewhere else. The
       call is
	      mount --bind olddir newdir
       After this call the same contents is accessible in two places.

       This  call attaches only (part of) a single filesystem, not possible submounts. The entire
       file hierarchy including submounts is attached a second place using
	      mount --rbind olddir newdir

       Since Linux 2.5.1 it is possible to atomically move a subtree to another place.	The  call
	      mount --move olddir newdir

       The  proc  file	system	is not associated with a special device, and when mounting it, an
       arbitrary keyword, such as proc can be used instead of a device specification.  (The  cus-
       tomary  choice  none  is  less fortunate: the error message `none busy' from umount can be

       Most devices are indicated by a file name (of a block special device), like /dev/sda1, but
       there  are  other possibilities. For example, in the case of an NFS mount, device may look
       like knuth.cwi.nl:/dir.	It is possible to indicate a block special device using its  vol-
       ume label or UUID (see the -L and -U options below).

       The  file /etc/fstab (see fstab(5)), may contain lines describing what devices are usually
       mounted where, using which options. This file is used in three ways:

       (i) The command
	      mount -a [-t type] [-O optlist]
       (usually given in a bootscript) causes all file systems mentioned in fstab (of the  proper
       type  and/or  having  or not having the proper options) to be mounted as indicated, except
       for those whose line contains the noauto keyword. Adding the -F	option	will  make  mount
       fork, so that the filesystems are mounted simultaneously.

       (ii)  When mounting a file system mentioned in fstab, it suffices to give only the device,
       or only the mount point.

       (iii) Normally, only the superuser can mount file systems.  However, when  fstab  contains
       the user option on a line, then anybody can mount the corresponding system.

       Thus, given a line
	      /dev/cdrom  /cd  iso9660	ro,user,noauto,unhide
       any user can mount the iso9660 file system found on his CDROM using the command
	      mount /dev/cdrom
	      mount /cd
       For  more  details,  see fstab(5).  Only the user that mounted a filesystem can unmount it
       again.  If any user should be able to unmount, then use users instead of user in the fstab
       line.   The owner option is similar to the user option, with the restriction that the user
       must be the owner of the special file. This may be useful e.g.  for  /dev/fd  if  a  login
       script makes the console user owner of this device.

       The  programs  mount  and  umount maintain a list of currently mounted file systems in the
       file /etc/mtab.	If no arguments are given to mount, this list is printed.  When the  proc
       filesystem is mounted (say at /proc), the files /etc/mtab and /proc/mounts have very simi-
       lar contents. The former has somewhat more information, such as the  mount  options  used,
       but  is	not  necessarily  up-to-date (cf. the -n option below). It is possible to replace
       /etc/mtab by a symbolic link to /proc/mounts, but some information is lost that	way,  and
       in particular working with the loop device will be less convenient.

       The  full  set of options used by an invocation of mount is determined by first extracting
       the options for the file system from the fstab table, then applying any options	specified
       by the -o argument, and finally applying a -r or -w option, when present.

       Options available for the mount command:

       -V     Output version.

       -h     Print a help message.

       -v     Verbose mode.

       -a     Mount all filesystems (of the given types) mentioned in fstab.

       -F     (Used  in  conjunction  with  -a.)   Fork  off  a new incarnation of mount for each
	      device.  This will do the mounts on different devices or different NFS  servers  in
	      parallel.  This has the advantage that it is faster; also NFS timeouts go in paral-
	      lel. A disadvantage is that the mounts are done in undefined order.  Thus, you can-
	      not use this option if you want to mount both /usr and /usr/spool.

       -f     Causes  everything  to be done except for the actual system call; if it's not obvi-
	      ous, this ``fakes'' mounting the file system.  This option is useful in conjunction
	      with  the  -v flag to determine what the mount command is trying to do. It can also
	      be used to add entries for devices that were mounted earlier with the -n option.

       -l     Add the ext2, ext3 and XFS labels in the mount output. Mount must  have  permission
	      to  read	the disk device (e.g. be suid root) for this to work.  One can set such a
	      label for ext2 or ext3 using the e2label(8) utility, or for XFS using xfs_admin(8).

       -n     Mount without writing in /etc/mtab.  This is necessary for example when /etc is  on
	      a read-only file system.

       -s     Tolerate	sloppy	mount options rather than failing. This will ignore mount options
	      not supported by a filesystem type. Not all filesystems support this  option.  This
	      option exists for support of the Linux autofs-based automounter.

       -r     Mount the file system read-only. A synonym is -o ro.

       -w     Mount the file system read/write. This is the default. A synonym is -o rw.

       -L label
	      Mount the partition that has the specified label.

       -U uuid
	      Mount  the  partition  that  has the specified uuid.  These two options require the
	      file /proc/partitions (present since Linux 2.1.116) to exist.

       -t vfstype
	      The argument following the -t is used to indicate the file system type.	The  file
	      system types which are currently supported are: adfs, affs, autofs, coda, coherent,
	      cramfs, devpts, efs, ext, ext2, ext3, hfs, hpfs, iso9660, jfs, minix, msdos, ncpfs,
	      nfs,  ntfs,  proc, qnx4, ramfs, reiserfs, romfs, smbfs, sysv, tmpfs, udf, ufs, ums-
	      dos, vfat, xenix, xfs, xiafs.  Note that coherent, sysv and  xenix  are  equivalent
	      and that xenix and coherent will be removed at some point in the future -- use sysv
	      instead. Since kernel version 2.1.21 the types ext and xiafs do not exist anymore.

	      For most types all the mount program has to do is issue a  simple  mount(2)  system
	      call,  and  no  detailed	knowledge  of the filesystem type is required.	For a few
	      types however (like nfs, smbfs, ncpfs) ad hoc code is necessary.	The  nfs  ad  hoc
	      code  is	built  in, but smbfs and ncpfs have a separate mount program. In order to
	      make it possible to treat all types in a uniform way, mount will execute	the  pro-
	      gram  /sbin/mount.TYPE  (if that exists) when called with type TYPE.  Since various
	      versions	of   the   smbmount   program	have   different   calling   conventions,
	      /sbin/mount.smb may have to be a shell script that sets up the desired call.

	      The  type iso9660 is the default.  If no -t option is given, or if the auto type is
	      specified, the superblock is probed for the filesystem  type  (adfs,  bfs,  cramfs,
	      ext,  ext2, ext3, hfs, hpfs, iso9660, jfs, minix, ntfs, qnx4, reiserfs, romfs, udf,
	      ufs, vxfs, xfs, xiafs are supported).  If this probe fails, mount will try to  read
	      the  file  /etc/filesystems, or, if that does not exist, /proc/filesystems.  All of
	      the filesystem types listed there will be tried, except for those that are  labeled
	      "nodev"  (e.g.,  devpts,	proc and nfs).	If /etc/filesystems ends in a line with a
	      single * only, mount will read /proc/filesystems afterwards.

	      The  auto  type  may  be	useful	for  user-mounted  floppies.   Creating  a   file
	      /etc/filesystems	can be useful to change the probe order (e.g., to try vfat before
	      msdos) or if you use a kernel module  autoloader.   Warning:  the  probing  uses	a
	      heuristic  (the  presence  of  appropriate  `magic'), and could recognize the wrong
	      filesystem type, possibly with catastrophic consequences. If your data is valuable,
	      don't ask mount to guess.

	      More  than  one  type may be specified in a comma separated list.  The list of file
	      system types can be prefixed with no to specify the file system types on	which  no
	      action should be taken.  (This can be meaningful with the -a option.)

	      For example, the command:
		     mount -a -t nomsdos,ext
	      mounts all file systems except those of type msdos and ext.

       -O     Used  in	conjunction  with  -a, to limit the set of filesystems to which the -a is
	      applied.	Like -t in this regard except that it is useless except in the context of
	      -a.  For example, the command:
		     mount -a -O no_netdev
	      mounts all file systems except those which have the option _netdev specified in the
	      options field in the /etc/fstab file.

	      It is different from -t in that each option is matched exactly; a leading no at the
	      beginning of one option does not negate the rest.

	      The -t and -O options are cumulative in effect; that is, the command
		     mount -a -t ext2 -O _netdev
	      mounts  all  ext2 filesystems with the _netdev option, not all filesystems that are
	      either ext2 or have the _netdev option specified.

       -o     Options are specified with a -o flag  followed  by  a  comma  separated  string  of
	      options.	 Some of these options are only useful when they appear in the /etc/fstab
	      file.  The following options apply to any file system that is  being  mounted  (but
	      not every file system actually honors them - e.g., the sync option today has effect
	      only for ext2, ext3 and ufs):

	      async  All I/O to the file system should be done asynchronously.

	      atime  Update inode access time for each access. This is the default.

	      auto   Can be mounted with the -a option.

		     Use default options: rw, suid, dev, exec, auto, nouser, and async.

	      dev    Interpret character or block special devices on the file system.

	      exec   Permit execution of binaries.

		     The filesystem resides on a device that requires  network	access	(used  to
		     prevent the system from attempting to mount these filesystems until the net-
		     work has been enabled on the system).

		     Do not update inode access times on this file system (e.g, for faster access
		     on the news spool to speed up news servers).

	      noauto Can  only be mounted explicitly (i.e., the -a option will not cause the file
		     system to be mounted).

	      nodev  Do not interpret character or block special devices on the file system.

	      noexec Do not allow execution of any binaries on the  mounted  file  system.   This
		     option  might  be useful for a server that has file systems containing bina-
		     ries for architectures other than its own.

	      nosuid Do not  allow  set-user-identifier  or  set-group-identifier  bits  to  take
		     effect.  (This  seems  safe,  but is in fact rather unsafe if you have suid-
		     perl(1) installed.)

	      nouser Forbid an ordinary (i.e., non-root) user to mount the file system.  This  is
		     the default.

		     Attempt to remount an already-mounted file system.  This is commonly used to
		     change the mount flags for a file system, especially to make a readonly file
		     system writeable. It does not change device or mount point.

	      ro     Mount the file system read-only.

	      rw     Mount the file system read-write.

	      suid   Allow set-user-identifier or set-group-identifier bits to take effect.

	      sync   All I/O to the file system should be done synchronously.

		     All  directory  updates within the file system should be done synchronously.
		     This affects the following  system  calls:  creat,  link,	unlink,  symlink,
		     mkdir, rmdir, mknod and rename.

	      user   Allow  an	ordinary user to mount the file system.  The name of the mounting
		     user is written to mtab so that he can unmount the file system again.   This
		     option  implies  the options noexec, nosuid, and nodev (unless overridden by
		     subsequent options, as in the option line user,exec,dev,suid).

	      users  Allow every user to mount and unmount the file system.  This option  implies
		     the  options  noexec,  nosuid,  and  nodev  (unless overridden by subsequent
		     options, as in the option line users,exec,dev,suid).

       --bind Remount a subtree somewhere else (so  that  its  contents  are  available  in  both
	      places). See above.

       --move Move a subtree to some other place. See above.

       The  following  options	apply only to certain file systems.  We sort them by file system.
       They all follow the -o flag.

Mount options for adfs
       uid=value and gid=value
	      Set the owner and group of the files in the file system (default: uid=gid=0).

       ownmask=value and othmask=value
	      Set the permission mask for  ADFS  'owner'  permissions  and  'other'  permissions,
	      respectively (default: 0700 and 0077, respectively).  See also /usr/src/linux/Docu-

Mount options for affs
       uid=value and gid=value
	      Set the owner and group of the root of the file  system  (default:  uid=gid=0,  but
	      with  option  uid  or  gid  without specified value, the uid and gid of the current
	      process are taken).

       setuid=value and setgid=value
	      Set the owner and group of all files.

	      Set the mode of all files to value & 0777 disregarding  the  original  permissions.
	      Add search permission to directories that have read permission.  The value is given
	      in octal.

	      Do not allow any changes to the protection bits on the file system.

       usemp  Set uid and gid of the root of the file system to the uid  and  gid  of  the  mount
	      point upon the first sync or umount, and then clear this option. Strange...

	      Print an informational message for each successful mount.

	      Prefix used before volume name, when following a link.

	      Prefix (of length at most 30) used before '/' when following a symbolic link.

	      (Default: 2.) Number of unused blocks at the start of the device.

	      Give explicitly the location of the root block.

	      Give blocksize. Allowed values are 512, 1024, 2048, 4096.

       grpquota / noquota / quota / usrquota
	      These  options  are  accepted  but ignored.  (However, quota utilities may react to
	      such strings in /etc/fstab.)

Mount options for coherent

Mount options for devpts
       The devpts file system is a pseudo file system, traditionally  mounted  on  /dev/pts.   In
       order  to  acquire  a pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
       terminal is then made available to the process  and  the  pseudo  terminal  slave  can  be
       accessed as /dev/pts/<number>.

       uid=value and gid=value
	      This  sets  the  owner  or the group of newly created PTYs to the specified values.
	      When nothing is specified, they will be set to the UID  and  GID	of  the  creating
	      process.	 For  example,	if there is a tty group with GID 5, then gid=5 will cause
	      newly created PTYs to belong to the tty group.

	      Set the mode of newly created PTYs to the specified value.  The default is 0600.	A
	      value of mode=620 and gid=5 makes "mesg y" the default on newly created PTYs.

Mount options for ext
       None.   Note  that  the	`ext' file system is obsolete. Don't use it.  Since Linux version
       2.1.21 extfs is no longer part of the kernel source.

Mount options for ext2
       The `ext2' file system is the standard Linux file system.  Due to a kernel bug, it may  be
       mounted with random mount options (fixed in Linux 2.0.4).

       bsddf / minixdf
	      Set the behaviour for the statfs system call. The minixdf behaviour is to return in
	      the f_blocks field the total number of blocks of the file system, while  the  bsddf
	      behaviour  (which  is  the  default) is to subtract the overhead blocks used by the
	      ext2 file system and not available for file storage. Thus

       % mount /k -o minixdf; df /k; umount /k
       Filesystem   1024-blocks  Used Available Capacity Mounted on
       /dev/sda6      2630655	86954  2412169	    3%	 /k
       % mount /k -o bsddf; df /k; umount /k
       Filesystem   1024-blocks  Used Available Capacity Mounted on
       /dev/sda6      2543714	   13  2412169	    0%	 /k

       (Note that this example shows that one can add command line options to the  options  given
       in /etc/fstab.)

       check / check=normal / check=strict
	      Set  checking level. When at least one of these options is set (and check=normal is
	      set by default) the inodes and blocks bitmaps are checked  upon  mount  (which  can
	      take half a minute or so on a big disk, and is rather useless).  With strict check-
	      ing, block deallocation checks that the block to free is in the data zone.

       check=none / nocheck
	      No checking is done. This is fast. Recent kernels do not have a check  option  any-
	      more - checking with e2fsck(8) is more meaningful.

       debug  Print debugging info upon each (re)mount.

       errors=continue / errors=remount-ro / errors=panic
	      Define  the behaviour when an error is encountered.  (Either ignore errors and just
	      mark the file system erroneous and continue, or remount the file system  read-only,
	      or  panic  and  halt the system.)  The default is set in the filesystem superblock,
	      and can be changed using tune2fs(8).

       grpid or bsdgroups / nogrpid or sysvgroups
	      These options define what group id a newly created file gets.  When grpid  is  set,
	      it  takes  the  group  id  of  the directory in which it is created; otherwise (the
	      default) it takes the fsgid of the current process, unless the  directory  has  the
	      setgid  bit set, in which case it takes the gid from the parent directory, and also
	      gets the setgid bit set if it is a directory itself.

       resgid=n and resuid=n
	      The ext2 file system reserves a certain  percentage  of  the  available  space  (by
	      default 5%, see mke2fs(8) and tune2fs(8)).  These options determine who can use the
	      reserved blocks.	(Roughly: whoever has the specified uid, or belongs to the speci-
	      fied group.)

       sb=n   Instead  of  block  1,  use  block  n  as superblock. This could be useful when the
	      filesystem has been damaged.  (Earlier, copies of  the  superblock  would  be  made
	      every 8192 blocks: in block 1, 8193, 16385, ... (and one got hundreds or even thou-
	      sands of copies on a big filesystem). Since version 1.08, mke2fs has a  -s  (sparse
	      superblock)  option  to  reduce the number of backup superblocks, and since version
	      1.15 this is the default. Note that this may mean that ext2 filesystems created  by
	      a  recent  mke2fs  cannot be mounted r/w under Linux 2.0.*.)  The block number here
	      uses 1k units. Thus, if you want to use logical block 32768 on a filesystem with 4k
	      blocks, use "sb=131072".

       grpquota / noquota / quota / usrquota
	      These options are accepted but ignored.

	      Disables	32-bit	UIDs  and  GIDs.  This is for interoperability with older kernels
	      which only store and expect 16-bit values.

Mount options for ext3
       The `ext3' file system is version of the ext2 file system which	has  been  enhanced  with
       journalling.  It supports the same options as ext2 as well as the following additions:

	      Update the ext3 file system's journal to the current format.

	      When  a journal already exists, this option is ignored. Otherwise, it specifies the
	      number of the inode which will represent the ext3 file system's journal file;  ext3
	      will  create  a  new  journal, overwriting the old contents of the file whose inode
	      number is inum.

       noload Do not load the ext3 file system's journal on mounting.

       data=journal / data=ordered / data=writeback
	      Specifies the journalling mode for file data.  Metadata is always journaled.

		     All data is committed into the journal prior to being written into the  main
		     file system.

		     This  is the default mode.  All data is forced directly out to the main file
		     system prior to its metadata being committed to the journal.

		     Data ordering is not preserved - data may be written into the main file sys-
		     tem  after its metadata has been committed to the journal.  This is rumoured
		     to be the highest-throughput option.  It  guarantees  internal  file  system
		     integrity,  however  it  can allow old data to appear in files after a crash
		     and journal recovery.

Mount options for fat
       (Note: fat is not a separate filesystem, but a common part of the msdos, umsdos	and  vfat

       blocksize=512 / blocksize=1024 / blocksize=2048
	      Set blocksize (default 512).

       uid=value and gid=value
	      Set  the	owner  and  group  of all files. (Default: the uid and gid of the current

	      Set the umask (the bitmask of the permissions that are not present). The default is
	      the umask of the current process.  The value is given in octal.

	      Set the umask applied to directories only.  The default is the umask of the current
	      process.	The value is given in octal. Present since 2.5.43.

	      Set the umask applied to regular files only.  The default is the umask of the  cur-
	      rent process.  The value is given in octal. Present since 2.5.43.

	      Three different levels of pickyness can be chosen:

		     Upper  and lower case are accepted and equivalent, long name parts are trun-
		     cated (e.g.  verylongname.foobar becomes verylong.foo), leading and embedded
		     spaces are accepted in each name part (name and extension).

		     Like  "relaxed",  but  many  special  characters (*, ?, <, spaces, etc.) are
		     rejected.	This is the default.

		     Like "normal", but names may not contain long parts and  special  characters
		     that  are	sometimes  used  on  Linux,  but  are  not accepted by MS-DOS are
		     rejected. (+, =, spaces, etc.)

	      Sets the codepage for converting to shortname characters on FAT and  VFAT  filesys-
	      tems. By default, codepage 437 is used.

       conv=b[inary] / conv=t[ext] / conv=a[uto]
	      The fat file system can perform CRLF<-->NL (MS-DOS text format to UNIX text format)
	      conversion in the kernel. The following conversion modes are available:

	      binary no translation is performed.  This is the default.

	      text   CRLF<-->NL translation is performed on all files.

	      auto   CRLF<-->NL translation is performed on all files that don't  have	a  "well-
		     known  binary"  extension.  The list of known extensions can be found at the
		     beginning of fs/fat/misc.c (as of 2.0, the list is: exe, com, bin, app, sys,
		     drv, ovl, ovr, obj, lib, dll, pif, arc, zip, lha, lzh, zoo, tar, z, arj, tz,
		     taz, tzp, tpz, gz, tgz, deb, gif, bmp, tif, gl, jpg, pcx, tfm, vf,  gf,  pk,
		     pxl, dvi).

	      Programs	that  do  computed  lseeks won't like in-kernel text conversion.  Several
	      people have had their data ruined by this translation. Beware!

	      For file systems mounted in binary  mode,  a  conversion	tool  (fromdos/todos)  is

	      Forces the driver to use the CVF (Compressed Volume File) module cvf_module instead
	      of auto-detection. If the kernel supports kmod, the cvf_format=xxx option also con-
	      trols on-demand CVF module loading.

	      Option passed to the CVF module.

       debug  Turn on the debug flag.  A version string and a list of file system parameters will
	      be printed (these data are also printed if the parameters appear	to  be	inconsis-

       fat=12 / fat=16 / fat=32
	      Specify  a  12,  16 or 32 bit fat.  This overrides the automatic FAT type detection
	      routine.	Use with caution!

	      Character set to use for converting between 8 bit characters  and  16  bit  Unicode
	      characters. The default is iso8859-1.  Long filenames are stored on disk in Unicode

       quiet  Turn on the quiet flag.  Attempts to chown or chmod files  do  not  return  errors,
	      although they fail. Use with caution!

       sys_immutable, showexec, dots, nodots, dotsOK=[yes|no]
	      Various misguided attempts to force Unix or DOS conventions onto a FAT file system.

Mount options for hpfs
       uid=value and gid=value
	      Set  the	owner  and  group  of all files. (Default: the uid and gid of the current

	      Set the umask (the bitmask of the permissions that are not present). The default is
	      the umask of the current process.  The value is given in octal.

       case=lower / case=asis
	      Convert all files names to lower case, or leave them.  (Default: case=lower.)

       conv=binary / conv=text / conv=auto
	      For  conv=text,  delete  some  random  CRs (in particular, all followed by NL) when
	      reading a file.  For conv=auto, choose more or less at random  between  conv=binary
	      and  conv=text.	For  conv=binary,  just  read  what  is  in the file. This is the

	      Do not abort mounting when certain consistency checks fail.

Mount options for iso9660
       ISO 9660 is a standard describing a filesystem structure to  be	used  on  CD-ROMs.  (This
       filesystem type is also seen on some DVDs. See also the udf filesystem.)

       Normal  iso9660	filenames appear in a 8.3 format (i.e., DOS-like restrictions on filename
       length), and in addition all characters are in upper case.  Also there  is  no  field  for
       file ownership, protection, number of links, provision for block/character devices, etc.

       Rock  Ridge  is	an  extension  to  iso9660 that provides all of these unix like features.
       Basically there are extensions to each directory record that supply all of the  additional
       information,  and  when	Rock  Ridge is in use, the filesystem is indistinguishable from a
       normal UNIX file system (except that it is read-only, of course).

       norock Disable the use of Rock Ridge extensions, even if available. Cf. map.

	      Disable the use of Microsoft Joliet extensions, even if available. Cf. map.

       check=r[elaxed] / check=s[trict]
	      With check=relaxed, a filename is first converted to lower case  before  doing  the
	      lookup.	This  is  probably  only  meaningful together with norock and map=normal.
	      (Default: check=strict.)

       uid=value and gid=value
	      Give all files in the file system the indicated user or group id, possibly overrid-
	      ing the information found in the Rock Ridge extensions.  (Default: uid=0,gid=0.)

       map=n[ormal] / map=o[ff] / map=a[corn]
	      For non-Rock Ridge volumes, normal name translation maps upper to lower case ASCII,
	      drops a trailing `;1', and converts `;' to `.'.  With map=off no	name  translation
	      is done. See norock.  (Default: map=normal.)  map=acorn is like map=normal but also
	      apply Acorn extensions if present.

	      For non-Rock Ridge volumes, give all files the indicated mode.  (Default: read per-
	      mission for everybody.)  Since Linux 2.1.37 one no longer needs to specify the mode
	      in decimal. (Octal is indicated by a leading 0.)

       unhide Also show hidden and associated files.

	      Set the block size to the indicated value.  (Default: block=1024.)

       conv=a[uto] / conv=b[inary] / conv=m[text] / conv=t[ext]
	      (Default: conv=binary.)  Since Linux 1.3.54 this	option	has  no  effect  anymore.
	      (And non-binary settings used to be very dangerous, possibly leading to silent data

       cruft  If the high byte of the file length contains other garbage, set this  mount  option
	      to  ignore the high order bits of the file length.  This implies that a file cannot
	      be larger than 16MB.  The `cruft' option is set automatically if the  entire  CDROM
	      has  a  weird  size  (negative,  or  more  than  800MB). It is also set when volume
	      sequence numbers other than 0 or 1 are seen.

	      Select number of session on multisession CD. (Since 2.3.4.)

	      Session begins from sector xxx. (Since 2.3.4.)

Mount options for minix

Mount options for msdos
       See mount options for fat.  If the msdos file system detects an inconsistency, it  reports
       an  error  and sets the file system read-only. The file system can be made writeable again
       by remounting it.

Mount options for ncp
       Just like nfs, the ncp implementation expects a binary argument (a struct  ncp_mount_data)
       to the mount system call. This argument is constructed by ncpmount(8) and the current ver-
       sion of mount (2.6h) does not know anything about ncp.

Mount options for nfs
       Instead of a textual option string, parsed by the kernel, the nfs file  system  expects	a
       binary  argument  of type struct nfs_mount_data.  The program mount itself parses the fol-
       lowing options of the form `tag=value', and puts them in the structure mentioned: rsize=n,
       wsize=n,  timeo=n,  retrans=n,  acregmin=n, acregmax=n, acdirmin=n, acdirmax=n, actimeo=n,
       retry=n,  port=n,  mountport=n,	mounthost=name,  mountprog=n,	mountvers=n,   nfsprog=n,
       nfsvers=n, namlen=n.  The option addr=n is accepted but ignored.  Also the following Bool-
       ean options, possibly preceded by no are recognized: bg, fg, soft, hard, intr, posix, cto,
       ac, tcp, udp, lock.  For details, see nfs(5).

       Especially useful options include

	      This  will  make	your  nfs  connection faster than with the default buffer size of
	      4096. (NFSv2 does not work with larger values of rsize and wsize.)

       hard   The program accessing a file on a NFS mounted file system will hang when the server
	      crashes.	The process cannot be interrupted or killed unless you also specify intr.
	      When the NFS server is back online the program will continue undisturbed from where
	      it was. This is probably what you want.

       soft   This  option  allows the kernel to time out if the nfs server is not responding for
	      some time. The time can be specified with timeo=time.  This option might be  useful
	      if your nfs server sometimes doesn't respond or will be rebooted while some process
	      tries to get a file from the server.  Usually it just causes lots of trouble.

       nolock Do not use locking. Do not start lockd.

Mount options for ntfs
	      Character set to use when returning file names.  Unlike VFAT, NTFS suppresses names
	      that contain unconvertible characters.

       utf8   Use UTF-8 for converting file names.

	      For 0 (or `no' or `false'), do not use escape sequences for unknown Unicode charac-
	      ters.  For 1 (or `yes' or `true') or 2,  use  vfat-style	4-byte	escape	sequences
	      starting	with ":". Here 2 give a little-endian encoding and 1 a byteswapped bigen-
	      dian encoding.

	      If enabled (posix=1), the file system distinguishes between upper and  lower  case.
	      The 8.3 alias names are presented as hard links instead of being suppressed.

       uid=value, gid=value and umask=value
	      Set  the file permission on the filesystem.  The umask value is given in octal.  By
	      default, the files are owned by root and not readable by somebody else.

Mount options for proc
       uid=value and gid=value
	      These options are recognized, but have no effect as far as I can see.

Mount options for ramfs
       Ramfs is a memory based filesystem. Mount it and you have it. Unmount it and it	is  gone.
       Present since Linux 2.3.99pre4.	There are no mount options.

Mount options for reiserfs
       Reiserfs  is a journaling filesystem.  The reiserfs mount options are more fully described
       at http://www.namesys.com/mount-options.html.

       conv   Instructs version 3.6 reiserfs software to mount a version 3.5 file  system,  using
	      the  3.6	format for newly created objects. This file system will no longer be com-
	      patible with reiserfs 3.5 tools.

       hash=rupasov / hash=tea / hash=r5 / hash=detect
	      Choose which hash function reiserfs will use to find files within directories.

		     A hash invented by Yury Yu. Rupasov.  It is  fast	and  preserves	locality,
		     mapping  lexicographically  close	file  names  to  close hash values.  This
		     option should not be used, as it causes a high probability  of  hash  colli-

	      tea    A	Davis-Meyer  function  implemented  by Jeremy Fitzhardinge.  It uses hash
		     permuting bits in the name.  It gets high	randomness  and,  therefore,  low
		     probability of hash collisions at come CPU cost.  This may be used if EHASH-
		     COLLISION errors are experienced with the r5 hash.

	      r5     A modified version of the rupasov hash. It is used by  default  and  is  the
		     best  choice  unless  the file system has huge directories and unusual file-
		     name patterns.

	      detect Instructs mount to detect which hash function is in  use  by  examining  the
		     file  system being mounted,  and to write this information into the reiserfs
		     superblock. This is only useful on the first mount of  an	old  format  file

	      Tunes the block allocator. This may provide performance improvements in some situa-

	      Tunes the block allocator. This may provide performance improvements in some situa-

	      Disable the border allocator algorithm invented by Yury Yu. Rupasov.  This may pro-
	      vide performance improvements in some situations.

       nolog  Disable journalling. This will provide slight performance improvements in some sit-
	      uations  at  the	cost  of losing reiserfs's fast recovery from crashes.	Even with
	      this option turned on, reiserfs still performs all journalling operations, save for
	      actual  writes  into  its  journalling  area.  Implementation of nolog is a work in

       notail By default, reiserfs stores small files and `file tails' directly  into  its  tree.
	      This confuses some utilities such as LILO(8).  This option is used to disable pack-
	      ing of files into the tree.

	      Replay the transactions which are in the journal, but do	not  actually  mount  the
	      file system. Mainly used by reiserfsck.

	      A  remount option which permits online expansion of reiserfs partitions.	Instructs
	      reiserfs to assume that the device has number blocks.  This option is designed  for
	      use  with devices which are under logical volume management (LVM).  There is a spe-
	      cial resizer utility which can be obtained from  ftp://ftp.namesys.com/pub/reiserf-

Mount options for romfs

Mount options for smbfs
       Just  like nfs, the smb implementation expects a binary argument (a struct smb_mount_data)
       to the mount system call. This argument is constructed by smbmount(8) and the current ver-
       sion of mount (2.9w) does not know anything about smb.

Mount options for sysv

Mount options for tmpfs
       The  following  parameters accept a suffix k, m or g for Ki, Mi, Gi (binary kilo, mega and
       giga) and can be changed on remount.

	      Override default size of the filesystem.	The size is given in bytes,  and  rounded
	      down to entire pages.  The default is half of the memory.

	      Set number of blocks.

	      Set number of inodes.

       mode=  Set initial permissions of the root directory.

Mount options for udf
       udf  is	the  "Universal Disk Format" filesystem defined by the Optical Storage Technology
       Association, and is often used for DVD-ROM.  See also iso9660.

       gid=   Set the default group.

       umask= Set the default umask.  The value is given in octal.

       uid=   Set the default user.

       unhide Show otherwise hidden files.

	      Show deleted files in lists.

       strict Set strict conformance (unused).

       utf8   (unused).


       bs=    Set the block size. (May not work unless 2048.)

       novrs  Skip volume sequence recognition.

	      Set the CDROM session counting from 0. Default: last session.

	      Override standard anchor location. Default: 256.

	      Override the VolumeDesc location. (unused)

	      Override the PartitionDesc location. (unused)

	      Set the last block of the filesystem.

	      Override the fileset block location. (unused)

	      Override the root directory location. (unused)

Mount options for ufs
	      UFS is a file system widely used in different operating systems.	The  problem  are
	      differences  among  implementations.  Features  of some implementations are undocu-
	      mented, so its hard to recognize the type of ufs	automatically.	 That's  why  the
	      user must specify the type of ufs by mount option.  Possible values are:

	      old    Old  format  of  ufs, this is the default, read only.  (Don't forget to give
		     the -r option.)

	      44bsd  For filesystems created by a BSD-like system (NetBSD,FreeBSD,OpenBSD).

	      sun    For filesystems created by SunOS or Solaris on Sparc.

	      sunx86 For filesystems created by Solaris on x86.

		     For filesystems created by NeXTStep (on NeXT station) (currently read only).

		     For NextStep CDROMs (block_size == 2048), read-only.

		     For filesystems  created  by  OpenStep  (currently  read  only).	The  same
		     filesystem type is also used by Mac OS X.

	      Set behaviour on error:

	      panic  If an error is encountered, cause a kernel panic.

		     These  mount  options don't do anything at present; when an error is encoun-
		     tered only a console message is printed.

Mount options for umsdos
       See mount options for msdos.  The dotsOK option is explicitly killed by umsdos.

Mount options for vfat
       First of all, the mount options for fat are recognized.	The dotsOK option  is  explicitly
       killed by vfat.	Furthermore, there are

	      Translate unhandled Unicode characters to special escaped sequences.  This lets you
	      backup and restore filenames that are created with any Unicode characters.  Without
	      this option, a '?' is used when no translation is possible. The escape character is
	      ':' because it is otherwise illegal on the vfat  filesystem.  The  escape  sequence
	      that  gets  used,  where u is the unicode character, is: ':', (u & 0x3f), ((u>>6) &
	      0x3f), (u>>12).

       posix  Allow two files with names that only differ in case.

	      First try to make a short name without sequence number, before trying name~num.ext.

       utf8   UTF8 is the filesystem safe 8-bit encoding of Unicode that is used by the  console.
	      It can be be enabled for the filesystem with this option.  If `uni_xlate' gets set,
	      UTF8 gets disabled.


	      Defines the behaviour for creation and display of  filenames  which  fit	into  8.3
	      characters.  If a long name for a file exists, it will always be preferred display.
	      There are four modes:

	      lower  Force the short name to lower case upon display; store a long name when  the
		     short name is not all upper case.

	      win95  Force  the short name to upper case upon display; store a long name when the
		     short name is not all upper case.

	      winnt  Display the shortname as is; store a long name when the short  name  is  not
		     all lower case or all upper case.

	      mixed  Display  the  short name as is; store a long name when the short name is not
		     all upper case.

       The default is "lower".

Mount options for xenix

Mount options for xfs
	      Sets the preferred buffered I/O size (default size is 64K).  size must be expressed
	      as the logarithm (base2) of the desired I/O size.  Valid values for this option are
	      14 through 16, inclusive (i.e. 16K, 32K, and 64K bytes).	On  machines  with  a  4K
	      pagesize,  13 (8K bytes) is also a valid size.  The preferred buffered I/O size can
	      also be altered on an individual file basis using the ioctl(2) system call.

       dmapi  /  xdsm
	      Enable the DMAPI (Data Management API) event callouts.

	      Set the number of in-memory log buffers.	Valid numbers range from  2-8  inclusive.
	      The  default  value is 8 buffers for filesystems with a blocksize of 64K, 4 buffers
	      for filesystems with a blocksize of 32K, 3 buffers for filesystems with a blocksize
	      of  16K, and 2 buffers for all other configurations.  Increasing the number of buf-
	      fers may increase performance on some workloads at the cost of the memory used  for
	      the additional log buffers and their associated control structures.

	      Set  the	size of each in-memory log buffer.  Valid sizes are 16384 (16K) and 32768
	      (32K).  The default value for machines with more than  32MB  of  memory  is  32768,
	      machines with less memory use 16384 by default.

       logdev=device and rtdev=device
	      Use  an external log (metadata journal) and/or real-time device.	An XFS filesystem
	      has up to three parts: a data section, a log section, and a real-time section.  The
	      real-time  section  is  optional, and the log section can be separate from the data
	      section or contained within it.  Refer to xfs(5).

	      Data allocations will not be aligned at stripe unit boundaries.

	      Access timestamps are not updated when a file is read.

	      The filesystem will be mounted without running log recovery.  If the filesystem was
	      not  cleanly  unmounted, it is likely to be inconsistent when mounted in norecovery
	      mode.  Some files or directories may not be accessible because of  this.	 Filesys-
	      tems mounted norecovery must be mounted read-only or the mount will fail.

	      Make  writes to files opened with the O_SYNC flag set behave as if the O_DSYNC flag
	      had been used instead.  This can result in better performance without  compromising
	      data  safety.   However  if this option is in effect, timestamp updates from O_SYNC
	      writes can be lost if the system crashes.

       quota / usrquota / uqnoenforce
	      User disk quota accounting enabled, and limits (optionally) enforced.

       grpquota / gqnoenforce
	      Group disk quota accounting enabled and limits (optionally) enforced.

       sunit=value and swidth=value
	      Used to specify the stripe unit and width for a RAID device  or  a  stripe  volume.
	      value  must  be specified in 512-byte block units.  If this option is not specified
	      and the filesystem was made on a stripe volume or the stripe  width  or  unit  were
	      specified for the RAID device at mkfs time, then the mount system call will restore
	      the value from the superblock.  For filesystems that  are  made  directly  on  RAID
	      devices, these options can be used to override the information in the superblock if
	      the underlying disk layout changes after the  filesystem	has  been  created.   The
	      swidth  option  is  required  if the sunit option has been specified, and must be a
	      multiple of the sunit value.

Mount options for xiafs
       None. Although nothing is wrong with xiafs, it is not used much, and  is  not  maintained.
       Probably  one shouldn't use it.	Since Linux version 2.1.21 xiafs is no longer part of the
       kernel source.

       One further possible type is a mount via the loop device. For example, the command

	 mount /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024

       will set up the loop device /dev/loop3 to correspond to the file  /tmp/fdimage,	and  then
       mount  this  device  on	/mnt.  This type of mount knows about three options, namely loop,
       offset and encryption, that are really options to losetup(8).  If no explicit loop  device
       is  mentioned  (but  just  an option `-o loop' is given), then mount will try to find some
       unused loop device and use that.  If you are not so unwise as to make /etc/mtab a symbolic
       link to /proc/mounts then any loop device allocated by mount will be freed by umount.  You
       can also free a loop device by hand, using `losetup -d', see losetup(8).

       mount has the following return codes (the bits can be ORed):

       0      success

       1      incorrect invocation or permissions

       2      system error (out of memory, cannot fork, no more loop devices)

       4      internal mount bug or missing nfs support in mount

       8      user interrupt

       16     problems writing or locking /etc/mtab

       32     mount failure

       64     some mount succeeded

       /etc/fstab file system table
       /etc/mtab table of mounted file systems
       /etc/mtab~ lock file
       /etc/mtab.tmp temporary file

       mount(2),  umount(2),  fstab(5),  umount(8),  swapon(8),   nfs(5),   xfs(5),   e2label(8),
       xfs_admin(8), mountd(8), nfsd(8), mke2fs(8), tune2fs(8), losetup(8)

       It is possible for a corrupted file system to cause a crash.

       Some  Linux file systems don't support -o sync and -o dirsync (the ext2 and ext3 file sys-
       tems do support synchronous updates (a la BSD) when mounted with the sync option).

       The -o remount may not be able to change mount parameters (all ext2fs-specific parameters,
       except  sb,  are changeable with a remount, for example, but you can't change gid or umask
       for the fatfs).

       A mount command existed in Version 5 AT&T UNIX.

Linux 2.0				14 September 1997				 MOUNT(8)

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